Water resisting and anticorrosive painting method and the painted articles

ABSTRACT

A painting method which comprises applying to a substrate an undercoating composition comprising from 10 to 500 parts by weight of an alkylated polycyclic aromatic compound containing no nitrogen, oxygen or sulfur to the extent detectable by elementary analysis and having a mean molecular weight measured by the VPO method of from 250 to 600 and an aromatic ring-forming proton density measured by the nuclear magnetic resonance method of from 35 to 80%, and 100 parts by weight of a urethane resin, said under-coating composition further containing a hardening agent and then applying an over-coating composition comprising a curable resin selected from the group consisting of an epoxy resin, a urethane resin, and an alkyd resin.

llnited States Patent Enomoto 1 1 Feb.4,1975

[75] Inventor: Satoru Enomoto, Fukushima, Japan [73] Assignee: KurehaKagalru Kogyo K.K.,

Tokyo, Japan 22 Filed: .lan.26,1973

211 Appl.No.:326,657

Related 1.1.8. Application Data [63] Continuation-impart of Ser. No.68,553, Aug. 31,

1970, abandoned.

[30] Foreign Application Priority Data Aug. 30, 1969 Japan 44-68350 [52]US. Cl 117/75, 117/72, 117/92, 117/135, 260/336 UB [51] Int. Cl B321)15/08 [58] Field of Search 117/75, 72, 132 BE, 92,

117/161 KP, 132 B, 135; 260/336 EP, 33.6 UB

[56] References Cited UNITED STATES PATENTS 2,864,722 12/1958 Millar eta1. 117/72 2,906,720 9/1959 Simpson 117/132 BE X 3,062,771 11/1962Boenau et a1 [17/132 BE X 3,284,400 11/1966 Nelson et a1. 260/336 EP3,352,955 ll/1967 Pigott et a1 117/75 3,390,119 6/1968 Alexander et a1260/18 TN X 3,625,742 12/1971 Baldwin 117/75 Primary Examiner-Ralphl-lusack Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn &Macpeak [57] ABSTRACT A painting method which comprises applying to asub strate an undercoating composition comprising from 10 to 500 partsby weight of an alkylated polycyclic aromatic compound containing nonitrogen, oxygen or sulfur to the extent detectable by elementaryanalysis and having a mean molecular weight measured by the VP0 methodof from 250 to 600 and an aromatic ring-forming proton density measuredby the nuclear magnetic resonance method of from 35 to 80%, and 100parts by weight of a urethane resin, said undercoating compositionfurther containing a hardening agent and then applying an over-coatingcomposition comprising a curable resin selected from the groupconsisting of an epoxy resin, a urethane resin, and an alkyd resin.

7 Claims, No Drawings WATER RESISTING AND ANTICORROSRVE PAINTING METHODAND THE PAINTED ARTICLES CROSS-REFERENCE TO RELATED APPLICATION Thepresent application is a continuation-in-part of co-pending applicationSer. No. 68,553, filed Aug. 3 1. I970, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to a method of applying water-resisting andanticorrosive paint to a substrate and, more particularly, the presentinvention relates to a painting method comprising applying to thesubstrate an undercoating composition comprising a mixture of analkylated polycyclic aromatic compound and a curable resin and thenapplying an over-coating composition comprising a curable resin.

2. Description of the Prior Art Coal tars which have hitherto been usedas paint materials have sufficient water resisting and anticorrosiveproperties and may be satisfactory from this point of view but, inpractical use, they encounter various difficulties. That is, they havesuch faults that the color thereof is black, the quality is notconstant, they readily cause bleeding thus making over-coatingimpossible, etc. Therefore, although coal tars have excellentwaterresistance and corrosion-resistance properties, their use islimited to a narrow range.

On the other hand, since petroleum asphalts have an inferiorcompatibility with resins as compared with coal tars, they are notusually used.

Therefore, an object of this invention is to provide a method forapplying a novel paint composition that can overcome the aforesaiddifficulties without losing the specific merits of coal tars.

SUMMARY OF THE INVENTION The present inventor has discovered that byapplying to a substrate a mixture of 10 to 500 parts by weight of analkylated polycyclic aromatic compound and 100 parts by weight of acurable resin, such as a urethane resin as an under-coating material andthen applying an over-coating composition containing, as a curableresin, a resin such as an epoxy resin, a urethane resin, or an alkydresin, a thick paint coating having excellent water resistance andcorrosion resistance can be obtained without being accompanied by theundesirable formations of bleeding and other similar disadvantages.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The alkylatedpolycyclic aromatic compounds having the excellent properties asmentioned above are those compounds in which no oxygen, sulfur ornitrogen is detected by an elementary analysis, and which do no emit,therefore, and offensive odors, and which show a neutral property. Also,it is preferable for the purposes of this invention that the alkylatedpolycyclic aromatic compounds have a mean molecular weight of from 250to 600 measured by the VP method (i.e., a vapor pressureosmotic pressuremethod), If the mean molecular weight is less than the disclosed range,the viscosity of the aromatic compound is lowered and the volatilitythereof is increased, which makes the use of such alkylated polycyclicaromatics undesirable for paint compositions.

On the other hand, if the mean molecular weight of the aromatics isgreater than the above range, solidification of the alkylated aromaticsoccurs due to the increase in the softening point, which is undesirablein operation.

Moreover, it is also desirable that the alkylated polycyclic aromaticcompounds have an aromatic ringforming proton density measured bynuclear magnetic resonance of 35 to (the 1' value of tetramethyl silaneis defined to be l0 as the standard and a 1' value of less than 4represents the aromatic proton). An aromatic ring forming proton densityof less than 35% means that the alkylated polycyclic aromatics have longalkyl groups or an increased number of naphthenic rings, which resultsin reducing the compatibility of the aromatic compounds with the curableresin.

On the other hand, if the aromatic ring forming proton density is higherthan 80%, a solidification phenomenon occurs due to the increase ofaromaticity.

Furthermore, the general properties of the alkylated polycyclic aromaticcompounds used in this invention are as follows: a specific gravity of0.95 to l.l0, and (if liquid) a viscosity of higher than 2,000 c.p.s.(at 25 C), or (if solid) a softening point of about 25 C.

The alkylated polycyclic aromatic compounds of this invention arederived from, for example, residual oils obtained in the thermalcracking of petroleum fractions at temperatures of higher than 900 C.Typical of such residual oils are a bottom oil obtained from theproduction of ethylene by the decomposition of a light oil or theresidual oil obtained from the production of ethylene and acetylene bythe decomposition of petroleum. See, for example, HydrocarbonProcessing," November, I969.

To obtain the alkylated aromatics of this invention, the abovedescribedresidual oil is first subjected to a conventional hydrodesulfurizationtreatment. The product is then alkylated and finally, low boilingfractions boiling at less than 380 C are removed from the alkylatedproduct to provide the alkylated polycyclic aromatic compounds of thisinvention.

Any conventional hydrodesulfurization process can be employed and theprocess can be conducted in one or two steps. Similarly, anyconventional alkylation process is operable. Typical examples ofoperable hydrodesulfurization and alkylation techniques are as follows:

Conditions of a Typical Hydrodesulfurization Treatment Temperature (C)40 to 450 Pressure (kg/cm) 5 to 300 H """/Fracti l 3 to l5 LHSV (liquidhourly space velocity) Catalyst:

0.2 to l0 One or more metals or sulfides of tungsten, molybdenum,nickel, cobalt, etc, on a carrier such as alumina, diatomaceous earth,etc.

Conditions of a Typical Alkylation Treatment phosphoric acid, etc.

Generally, the alkylation is conducted using a lower olefin such as anethylene, propylene, or butylene in the presence of an acid catalystsuch as silica-alumina gel, etc.

Generally, the viscosity of the alkylated polycyclic aromatic compoundscan be varied at will by controlling, inter alia, the molecular weightof the raw material (i.e., the residual oils) and the degree ofalkylation. Specifically, as the molecular weight of the raw materialbecomes lower, the viscosity becomes lower. The residual oils generallyhave a high viscosity and are near-solids but by alkylating such oils,the viscosity will decrease. Continuing the alkylation (i.e., addingmore alkyl groups) beyond a certain point will result in furtherincreases in the viscosity.

Therefore, one may produce alkylated polycyclic aromatic compounds ofthe above type having any viscosity above 2000 cps at 25 C byconsidering the above factors.

According to the present invention, an under-coating composition isapplied using a mixture of to 500 parts by weight of the above-mentionedalkylated polycyclic aromatic compounds and 100 parts by weight of aurethane resin, the mixture further containing a hardening agent for theresin and, if necessary, a filler and a solvent; and, then, anover-coating composition is applied using a coating compositioncontaining, as the vehicle, a curable resin such as an epoxy resin, aurethane resin, or an alkyd resin.

The painting method of this invention has the advantages that the periodof time between the under-coating and the over-coating can be greatlyshortened as compared with conventional painting methods and nostripping of the coated layers occurs when completed. Also, when thepainted articles are subjected to a long weathering test, nobleeding-out phenomenon occurs, and when a titanium white-containingpaint is applied to the over-coat, no discoloring occurs. Also, thewater resistance and the corrosion resistance of the layers thusapainted are the same as, or superior to, those layers obtained using acoal tar-blended paint.

Thus, the painting method of this invention overcomes the abovementioneddisadvantages of conventional coal tar-blended paints, the coloringrange of the paint is greatly enlarged, and further, the mostinexpensive alkyd paint among the various baking paints can be used forthe over-coating.

The preferred substrate is metal, most preferably iron or steel.

The following examples illustrate several embodiments of the productionof the raw materials for the paint used in the method of this inventionand several embodiments of the painting method of this invention.

MANUFACTURED EXAMPLE 1 A crude oil from North Sumatra was sprayed into ahigh temperature steam at 2,000 C to cause the pyrolysis thereof andfrom the tarry materials thus obtained were recovered fractions havingboiling points of 250 to 450 C. These fractions were introduced in areactor containing a cobalt-molybdenum-alumina type desulfurizationcatalyst together with hydrogen under a pressure of 35 kg/cm atemperature of 410 C, a LHSV of 0.5, and a molar ratio of hydrogen tothe fraction of 6 to remove impurities from the fractions. Then, thefractions thus refined were alkylated by introducing them into a reactorcontaining a silica-alumina catalyst together with ethylene in anethylene/fractions molar ratio of 10 under the following conditions: apressure of 40 kg/cm, :1 LHSV of0.5, and a temperature of 300 C.Thereafter, by distilling the alkylation product, the

following two components A and B were obtained. The

properties thereof are also shown below.

Component A Component 8 Temperature of removing low boiling matter 380C430C Specific gravity 1.10 1.20

Viscosity (cps)(at 25C) l20,000 42,000

Volatile matter ("/11 0 0 Molecular weight (VPO) 310 460 Aromaticring-forming proton density (NMR) 367! 50% Elementary analysis N l nonenone 0 MANUFACTURED EXAMPLE 2 The fractions recovered from the tarrymaterials as in Example 1 were introduced in a reactor containing acobalt-molybdenum-alumina type desulfurization catalyst together withhydrogen under a pressure of 35 Kg/cm a temperature of 350 C, a LHSV of0.5, and a molar ratio of hydrogen to the fraction of 5 to removeimpurities from the fractions. Then, the fractions thus refined werealkylated by introducing them into a reactor containing a silica-aluminacatalyst together with propylene in a propylene/fractions molar ratio of3.0 under the following conditions: a pressure of 20 Kg/cm, a LHSV of0.5, and a temperature of 200 C. Thereafter, by distilling thealkylation product, the following component C was obtained. Theproperties thereof are also shown below.

Component C Temperature of removing low boiling matter 380C Specificgravity 0.99

Viscosity (cps) (at 25 C) 10,000

Volatile matter (/z) 0 MANUFACTURED EXAMPLE 3 A bottom oil formed duringthe production of ethylene by an outer heating-type steam decompositionof naphtha was recovered. The bottom oil was subjected to thedesulfurization as in Example 1 and then a part of the bottom oil thusdesulfurized was alkylated with ethylene as in Example 1 and thendistilled to remove low boiling matters of lower than 400 C to provideComponent D. The properties of this component are shown below.

Component D S ecil'ie ravitv L08 I p g prepared by mixing theabove-mentioned components Viscosity (CPS! (at 35Cl 14mm) 5 using eachofthe components A, B, C and D prepared Volatile matter W) o in theabove examples as the alkylated polycyclic aromatics and applied to aniron plate to a thickness of Welsh 800-] .000 microns. After drying thecoating for 1 day Aromatic-forming proton at normal temperature, theover-coating COmpOStttOtt (NMR) described above was applied to theunder-coat thus Elementary analysis' formed to a thickness of 50microns. The excellent re- N and 0 sults obtained by the method of thisinvention are shown in the following table.

Water Light Weathering (4) Impact Aromatic Over resis- Fast- Resis-Bending resis- Component Coat tancet l) ness(2) tance(3) Strengthtanee(5) Bleedingtoi A Urethane Resin 1 kg- Compono no no 50cm sitionchange change change passed passed none B do. do. do. do. do. do. do.

D do. do. do. do. do. do. do.

C do. do. do. do. do. do. do.

A Alkyd resin Composition do. do. do. do. do. do. do. do. do. do. do.do. do.

do. do. do. do. do. do. do.

C do. do. do. do. do. do. do.

(llWater resistance (immersed in distilled water for 3 months 41140 C);(ZlLight Fastncss (light exposed for 200 hours by means of afade-wmeterl; (JlWeathering resistance tallowed to stand outdoors for (amonths); (4JBending strength (an inch. mandrel test); (illmpactresistance (Du Pom-type test); and (filBlceding (observed after allowingto stand for (i months).

EXAMPLE 4 What is claimed is:

This example describes the use of a paint composition containing aurethane resin and the alkylated polycyclic aromatic compounds ofExamples l, 2 and 3.

Under-coating composition Urethane resin. Olestcr No. 1066 (trade name.made by Mitsui Toatsu Kagaku K.K.)

Alkylated polycyclic aromatic compound (described below) Colonate L(Trade Name) O\'ercoating composition 1. Urethane resin composition:

Urethane resin Olester No. 1066 Titanium white Colonate L Alkyd resincomposition:

Alkyd resin (Phthalkyd 3657()) Titanium white parts by weight 50 partsby weight parts by weight 25 parts by weight 25 parts by weight parts byweight I00 parts by weight 40 parts by weight Chemical Co., Japan, andis a prepolymer of tristyrolpropane and toluene diisocyanate.

The coating composition for the under-coating was 1. A coated articlehaving excellent water-resistance and corrosion-resistance and which isnon-bleeding comprising:

1. a substrate;

2. a first layer coated directly on said substrate consistingessentially of 10 to 500 parts by weight of an alkylated polycyclicaromatic compound and 100 parts by weight of a urethane resin, saidalkylated polycyclic aromatic compound containing no nitrogen, oxygen orsulfur to the extent detectable by elementary analysis, having a meansmolecular weight measured by VPO method of from 250 to 600, having anaromatic ring-forming proton den sity measured by the nuclear magneticresonance method of from 35 to having a specific gravity of from 0.95 to1.10, and, if liquid, having a viscosity of at least 2,000 eentipoisesat 25 C or, if solid, having a softening point of about 25 C; said firstlayer further consisting essentially ofa hardening agent for theurethane resin; and

3. a second layer coated directly on said first layer consistingessentially of a curable resin selected from the group consisting of anepoxy, a urethane resin and an alkyd resin.

2. A method of coating a substrate to provide said substrate withexcellent water-resistance and excellent corrosion-resistance and tomake said substrate nonbleeding comprising:

1. applying to said substrate an undercoating composition consistingessentially of 10 to 500 parts by weight of an alkylated polycyclicaromatic compound, 100 parts by weight of a urethane resin and ahardening agent for the urethane resin. said alkylated polycyclicaromatic compound containing no nitrogen, oxygen or sulfur to the extentdetectable by elementary analysis, having a mean molecular weightmeasured by the VP0 method of from 250 to 600, having an aromaticring-forming proton density measured by the nuclear magnetic resonancemethod of from 35 to 80%, having a specific gravity of from 0.95 to1.10, having a viscosity of at least 2,000 centipoises at C and having asoftening point of about 25 C; and

2. applying to the undercoated substrate an overcoating compositionconsisting essentially of a curable resin selected from the groupconsisting of an epoxy resin, a urethane resin and an alkyd resin.

3. The method of claim 2 wherein said alkylated polycyclic aromaticcompound is obtained by hydrodesulfurizing and alkylating a residual oilobtained in the thermal cracking of petroleum fractions at temperatureshigher than 900 C and subsequently removing low boiling fractions fromthe resulting product.

4. The method of claim 3 wherein said alkylation step is conducted witha lower olefin selected from the group consisting of ethylene. propyleneand butylene.

5. The method of claim 2 wherein said substrate comprises steel.

6. The method of claim 2 wherein the undercoating composition is driedbefore said overcoating composition is applied thereto.

7. The method of claim 2 wherein said uncoating composition furtherconsists essentially of a filler and

1. A SUBSTRATE;
 2. A FIRST LAYER COATED DIRECTLY ON SAID SUBSTRATECONSISTING ESSENTIALLY OF 10 TO 500 PARTS BY WEIGHT OF AN ALKYLATEDPOLYCYCLIC AROMATIC COMPOUND AND 100 PARTS BY WEIGHT OF A URETHANERESIN, SAID ALKYLATED POLYCYCLIC AROMATIC COMPOUND CONTAINING NONITROGEN, OXYGEN OR SULFUR TO THE EXTENT DETECTABLE BY ELEMENTARYANALYSIS, HAVING A MEANS MOLECULAR WEIGHT MEASURED BY VPO METHOD OF FROM250 TO 600, HAVING AN AROMATIC RING-FORMING PROTON DENSITY MEASURED BYTHE NUCLEAR MAGNETIC RESONANCE METHOD OF FROM 35 TO 80%, HAVING ASPECFIC GRAVITY OF FROM 0.95 TO 1.10, AND, IF LIQUID, HAVING A VISCOSITYOF AT LEAST 2,000 CENTIPOISES AT 25*C OR, IF SOLID, HAVING A SOFTENINGPOINT OF ABOUT 25*C; SAID FIRST LAYER FURTHER CONSISTING ESSENTIALLY OFA HARDENING AGENT FOR THE URETHANE RESIN; AND
 2. applying to theundercoated substrate an overcoating composition consisting essentiallyof a curable resin selected from the group consisting of an epoxy resin,a urethane resin and an alkyd resin.
 2. A method of coating a substrateto provide said substrate with excellent water-resistance and excellentcorrosion-resistance and to make said substrate non-bleeding comprising:2. a first layer coated directly on said substrate consistingessentially of 10 to 500 parts by weight of an alkylated polycyclicaromatic compound and 100 parts by weight of a urethane resin, saidalkylated polycyclic aromatic compound containing no nitrogen, oxygen orsulfur to the extent detectable by elementary analysis, having a meansmolecular weight measured by VPO method of from 250 to 600, having anaromatic ring-forming proton density measured by the nuclear magneticresonance method of from 35 to 80%, having a specific gravity of from0.95 to 1.10, and, if liquid, having a viscosity of at least 2,000centipoises at 25* C or, if solid, having a softening point of about 25*C; said first layer further consisting essentially of a hardening agentfor the urethane resin; and
 3. a second layer coated directly on saidfirst layer consisting essentially of a curable resin selected from thegroup consisting of an epoxy, a urethane resin and an alkyd resin.
 3. ASECOND LAYER COATED DIRECTLY ON SAID FIRST LAYER CONSISTING ESSENTIALLYOF A CURABLE RESIN SELECTED FROM THE GROUP CONSISTING OF AN EPOXY, AURETHANE RESIN AND AN ALKYD RESIN.
 3. The method of claim 2 wherein saidalkylated polycyclic aromatic compound is obtained by hydrodesulfurizingand alkylating a residual oil obtained in the thermal cracking ofpetroleum fractions at temperatures higher than 900* C and subsequentlyremoving low boiling fractions from the resulting product.
 4. The methodof claim 3 wherein said alkylation step is conducted with a lower olefinselected from the group consisting of ethylene, propylene and butylene.5. The method of claim 2 wherein said substrate comprises steel.
 6. Themethod of claim 2 wherein the undercoating composition is dried beforesaid overcoating composition is applied thereto.
 7. The method of claim2 wherein said uncoating composition further consists essentially of afiller and a solvent.